feat(web): book reviews — markdown, sibling of ratings, full API + page surface

media_reviews table mirrors media_ratings' shape (unique per user+item,
cascade deletes, updated_at for LWW) but standalone: a review without a
rating must work. Body is RAW MARKDOWN — storage and every payload carry
the source; rendering happens only at display sites (same doctrine as
notes, same sanitization pipeline: markdown-it + DOMPurify).

API: GET/PUT/DELETE /api/media-items/:id/review (PUT upserts; an empty
body deletes — clearing via an editor is a delete, not an empty row).
Book-detail page payload now carries the review beside the rating.

Page: the review renders above the synopsis as a scrolling card (same
max-height box as the summary), hydrated client-side through
renderNoteHtml; 'Write review'/'Edit review' sits next to the rating
stars and opens a raw-markdown editor dialog (save / delete / cancel).

sqlc regenerated; schema applied to the dev DB. Live-verified: upsert,
get, empty-delete, page markup, and the app round-trip against the dev
server.

internal/router/frontend.go

@@ -1603,6 +1603,17 @@ func registerFrontendRoutes(cfg *Config) {
 			rating = &userRating
 		}
 
+		// Fetch the user's review (raw markdown; rendered client-side
+		// through the notes pipeline).
+		var review *database.MediaReviews
+		userReview, err := cfg.Queries.GetMediaReview(c.Request().Context(), database.GetMediaReviewParams{
+			MediaItemID: pgMediaUUID,
+			UserID:      pgUserID,
+		})
+		if err == nil {
+			review = &userReview
+		}
+
 		// Fetch collections
 		collections, _ := cfg.Queries.GetCollectionsForBook(c.Request().Context(), pgMediaUUID)
 
@@ -1676,6 +1687,7 @@ func registerFrontendRoutes(cfg *Config) {
 			MediaItems:         mediaItem, // Embedded - ALL fields available
 			FileLocation:       fileLocation,
 			Rating:             rating,
+			Review:             review,
 			Collections:        collections,
 			ReadingProgress:    progress,
 			BookStats:          bookStats,

internal/router/media.go

@@ -25,6 +25,13 @@ func registerMediaRoutes(cfg *Config) {
 	protected.PUT("/media-items/:id/rating", cfg.MediaHandler.UpdateMediaRating)
 	protected.DELETE("/media-items/:id/rating", cfg.MediaHandler.DeleteMediaRating)
 
+	// Media review routes (all authenticated users). Raw markdown in,
+	// raw markdown out — rendered only at display sites.
+	protected.POST("/media-items/:id/review", cfg.MediaHandler.UpsertMediaReview)
+	protected.GET("/media-items/:id/review", cfg.MediaHandler.GetMediaReview)
+	protected.PUT("/media-items/:id/review", cfg.MediaHandler.UpsertMediaReview)
+	protected.DELETE("/media-items/:id/review", cfg.MediaHandler.DeleteMediaReview)
+
 	// Progress routes (all authenticated users)
 	protected.GET("/media-items/:id/progress", cfg.MediaHandler.GetMediaReadingProgress)
 	protected.PUT("/media-items/:id/progress", cfg.MediaHandler.UpdateMediaReadingProgress)